I found Tier 8 Bountiful Delves last night rough as an item level 584 Guardian Druid, but this morning at roughly 590 it was easier. The recommended item level is 600 after all, and I should be breezing past them after I get a few more upgrades (notably in the back or wrists slots). I don’t know how they are in groups except for the anecdotes here on the forums, so I can’t speak to that.